Refactor API to be more RFC compliant

Add docs

spec/accept_language_spec.cr

@@ -1,12 +1,12 @@
 require "./spec_helper"
 
 struct AcceptLanguageTest < ASPEC::TestCase
-  @[DataProvider("type_data_provider")]
+  @[DataProvider("accept_value_data_provider")]
-  def test_get_type(header : String?, expected : String?) : Nil
+  def test_accept_value(header : String?, expected : String?) : Nil
-    ANG::AcceptLanguage.new(header).type.should eq expected
+    ANG::AcceptLanguage.new(header).accept_value.should eq expected
   end
 
-  def type_data_provider : Tuple
+  def accept_value_data_provider : Tuple
     {
       {"en;q=0.7", "en"},
       {"en-GB;q=0.8", "en-gb"},
@@ -17,12 +17,12 @@ struct AcceptLanguageTest < ASPEC::TestCase
     }
   end
 
-  @[DataProvider("value_data_provider")]
+  @[DataProvider("header_data_provider")]
   def test_get_value(header : String?, expected : String?) : Nil
-    ANG::AcceptLanguage.new(header).value.should eq expected
+    ANG::AcceptLanguage.new(header).header.should eq expected
   end
 
-  def value_data_provider : Tuple
+  def header_data_provider : Tuple
     {
       {"en;q=0.7", "en;q=0.7"},
       {"en-GB;q=0.8", "en-GB;q=0.8"},

spec/accept_spec.cr

@@ -5,24 +5,24 @@ struct AcceptTest < ASPEC::TestCase
     ANG::Accept.new("foo/bar; q=1; hello=world").parameters["hello"]?.should eq "world"
   end
 
-  @[DataProvider("normalized_value_data_provider")]
+  @[DataProvider("normalized_header_data_provider")]
-  def test_normalized_value(header : String, expected : String) : Nil
+  def test_normalized_header(header : String, expected : String) : Nil
-    ANG::Accept.new(header).normalized_value.should eq expected
+    ANG::Accept.new(header).normalized_header.should eq expected
   end
 
-  def normalized_value_data_provider : Tuple
+  def normalized_header_data_provider : Tuple
     {
-      {"text/html; z=y; a=b; c=d", "text/html; z=y; a=b; c=d"},
+      {"text/html  ; z=y; a  = b; c=d", "text/html; a=b; c=d; z=y"},
       {"application/pdf; q=1; param=p", "application/pdf; param=p"},
     }
   end
 
-  @[DataProvider("type_data_provider")]
+  @[DataProvider("media_range_data_provider")]
-  def test_type(header : String, expected : String) : Nil
+  def test_media_range(header : String, expected : String) : Nil
-    ANG::Accept.new(header).type.should eq expected
+    ANG::Accept.new(header).media_range.should eq expected
   end
 
-  def type_data_provider : Tuple
+  def media_range_data_provider : Tuple
     {
       {"text/html;hello=world", "text/html"},
       {"application/pdf", "application/pdf"},
@@ -40,12 +40,12 @@ struct AcceptTest < ASPEC::TestCase
     }
   end
 
-  @[DataProvider("value_data_provider")]
+  @[DataProvider("header_data_provider")]
-  def test_value(header : String, expected : String) : Nil
+  def test_accept_value(header : String, expected : String) : Nil
-    ANG::Accept.new(header).value.should eq expected
+    ANG::Accept.new(header).header.should eq expected
   end
 
-  def value_data_provider : Tuple
+  def header_data_provider : Tuple
     {
       {"text/html;hello=world  ;q=0.5", "text/html;hello=world  ;q=0.5"},
       {"application/pdf", "application/pdf"},

spec/base_accept_spec.cr

@@ -5,12 +5,12 @@ private struct MockAccept < ANG::BaseAccept; end
 struct BaseAcceptTest < ASPEC::TestCase
   @[DataProvider("build_parameters_data_provider")]
   def test_build_parameters_string(header : String, expected : String) : Nil
-    MockAccept.new(header).normalized_value.should eq expected
+    MockAccept.new(header).normalized_header.should eq expected
   end
 
   def build_parameters_data_provider : Tuple
     {
-      {"media/type; xxx = 1.0;level=2;foo=bar", "media/type; xxx=1.0; level=2; foo=bar"},
+      {"media/type; xxx = 1.0;level=2;foo=bar", "media/type; foo=bar; level=2; xxx=1.0"},
     }
   end
 

spec/charset_negotiator_spec.cr

@@ -16,21 +16,21 @@ struct CharsetNegotiatorTest < NegotiatorTestCase
 
     accept = accept.should_not be_nil
     accept.should be_a ANG::AcceptCharset
-    accept.value.should eq "fr"
+    accept.charset.should eq "fr"
   end
 
   def test_best_respects_priorities : Nil
     accept = @negotiator.best "foo, bar, yo", {"yo"}
     accept = accept.should_not be_nil
     accept.should be_a ANG::AcceptCharset
-    accept.type.should eq "yo"
+    accept.charset.should eq "yo"
   end
 
   def test_best_respects_quality : Nil
     accept = @negotiator.best "utf-8;q=0.5,iso-8859-1", {"iso-8859-1;q=0.3", "utf-8;q=0.9", "utf-16;q=1.0"}
     accept = accept.should_not be_nil
     accept.should be_a ANG::AcceptCharset
-    accept.type.should eq "utf-8"
+    accept.charset.should eq "utf-8"
   end
 
   @[DataProvider("best_data_provider")]
@@ -41,7 +41,7 @@ struct CharsetNegotiatorTest < NegotiatorTestCase
       expected.should be_nil
     else
       accept.should be_a ANG::AcceptCharset
-      accept.value.should eq expected
+      accept.header.should eq expected
     end
   end
 

spec/encoding_negotiator_spec.cr

@@ -15,7 +15,7 @@ struct EncodingNegotiatorTest < NegotiatorTestCase
     accept = @negotiator.best "gzip;q=0.7,identity", {"identity;q=0.5", "gzip;q=0.9"}
     accept = accept.should_not be_nil
     accept.should be_a ANG::AcceptEncoding
-    accept.type.should eq "gzip"
+    accept.coding.should eq "gzip"
   end
 
   @[DataProvider("best_data_provider")]
@@ -26,7 +26,7 @@ struct EncodingNegotiatorTest < NegotiatorTestCase
       expected.should be_nil
     else
       accept.should be_a ANG::AcceptEncoding
-      accept.value.should eq expected
+      accept.header.should eq expected
     end
   end
 

spec/language_negotiator_spec.cr

@@ -11,7 +11,7 @@ struct LanguageNegotiatorTest < NegotiatorTestCase
     accept = @negotiator.best "en;q=0.5,de", {"de;q=0.3", "en;q=0.9"}
     accept = accept.should_not be_nil
     accept.should be_a ANG::AcceptLanguage
-    accept.type.should eq "en"
+    accept.language.should eq "en"
   end
 
   @[DataProvider("best_data_provider")]
@@ -22,7 +22,7 @@ struct LanguageNegotiatorTest < NegotiatorTestCase
       expected.should be_nil
     else
       accept.should be_a ANG::AcceptLanguage
-      accept.value.should eq expected
+      accept.header.should eq expected
     end
   end
 

spec/negotiator_spec.cr

@@ -11,7 +11,7 @@ struct NegotiatorTest < NegotiatorTestCase
     accept = @negotiator.best "text/html,text/*;q=0.7", {"text/html;q=0.5", "text/plain;q=0.9"}
     accept = accept.should_not be_nil
     accept.should be_a ANG::Accept
-    accept.type.should eq "text/plain"
+    accept.media_range.should eq "text/plain"
   end
 
   def test_best_invalid_unstrict
@@ -23,7 +23,7 @@ struct NegotiatorTest < NegotiatorTestCase
       @negotiator.best "foo/bar", {"/qwer"}
     end
 
-    ex.type.should eq "/qwer"
+    ex.media_range.should eq "/qwer"
   end
 
   @[DataProvider("best_data_provider")]
@@ -46,7 +46,7 @@ struct NegotiatorTest < NegotiatorTestCase
 
     expected = expected.should_not be_nil
 
-    accept_header.type.should eq expected[0]
+    accept_header.media_range.should eq expected[0]
     accept_header.parameters.should eq (expected[1] || Hash(String, String).new)
   end
 
@@ -114,7 +114,7 @@ struct NegotiatorTest < NegotiatorTestCase
 
     expected.each_with_index do |element, idx|
       elements[idx].should be_a ANG::Accept
-      element.should eq elements[idx].value
+      element.should eq elements[idx].header
     end
   end
 

src/abstract_negotiator.cr

@@ -1,3 +1,4 @@
+# Base negotiator type.  Implements logic common to all negotiators.
 abstract class Athena::Negotiation::AbstractNegotiator
   private record OrderKey, quality : Float32, index : Int32, value : String do
     include Comparable(self)
@@ -10,6 +11,9 @@ abstract class Athena::Negotiation::AbstractNegotiator
 
   private abstract def create_header(header : String) : ANG::BaseAccept
 
+  # Returns the best `ANG::BaseAccept` type based on the provided *header* value and *priorities*.
+  #
+  # See `Athena::Negotiation` for examples.
   def best(header : String, priorities : Indexable(String), strict : Bool = false) : ANG::BaseAccept?
     raise ArgumentError.new "priorities should not be empty." if priorities.empty?
     raise ArgumentError.new "The header string should not be empty." if header.blank?
@@ -37,6 +41,9 @@ abstract class Athena::Negotiation::AbstractNegotiator
     match.nil? ? nil : accepted_priorties[match.index]
   end
 
+  # Returns an array of `ANG::BaseAccept` types that the provided *header* allows, ordered so that the `#best` match is first.
+  #
+  # See `Athena::Negotiation` for examples.
   def ordered_elements(header : String) : Array(ANG::BaseAccept)
     raise ArgumentError.new "The header string should not be empty." if header.blank?
 
@@ -47,7 +54,7 @@ abstract class Athena::Negotiation::AbstractNegotiator
     self.parse_header(header) do |h|
       element = self.create_header h
       elements << element
-      order_keys << OrderKey.new element.quality, idx, element.value
+      order_keys << OrderKey.new element.quality, idx, element.header
     rescue ex
       # skip
     ensure
@@ -60,12 +67,12 @@ abstract class Athena::Negotiation::AbstractNegotiator
   end
 
   protected def match(header : ANG::BaseAccept, priority : ANG::BaseAccept, index : Int32) : ANG::AcceptMatch?
-    accept_type = header.type
+    accept_value = header.accept_value
-    priority_type = priority.type
+    priority_value = priority.accept_value
 
-    equal = accept_type.downcase == priority_type.downcase
+    equal = accept_value.downcase == priority_value.downcase
 
-    if equal || accept_type == "*"
+    if equal || accept_value == "*"
       return ANG::AcceptMatch.new header.quality * priority.quality, 1 * (equal ? 1 : 0), index
     end
 

src/accept.cr

@@ -1,21 +1,45 @@
 require "./base_accept"
 
+# Represents an [Accept](https://tools.ietf.org/html/rfc7231#section-5.3.2) header media type.
+#
+# ```
+# accept = ANG::Accept.new "application/json; q = 0.75; charset = UTF-8"
+#
+# accept.header            # => "application/json; q = 0.9; charset = UTF-8"
+# accept.normalized_header # => "application/json; charset=UTF-8"
+# accept.parameters        # => {"charset" => "UTF-8"}
+# accept.quality           # => 0.75
+# accept.type              # => "application"
+# accept.sub_type          # => "json"
+# ```
 struct Athena::Negotiation::Accept < Athena::Negotiation::BaseAccept
-  getter base_part : String
+  # Returns the type for this `Accept` header.
-  getter sub_part : String
+  # E.x. if the `#media_range` is `application/json`, the type would be `application`.
+  getter type : String
+
+  # Returns the sub type for this `Accept` header.
+  # E.x. if the `#media_range` is `application/json`, the sub type would be `json`.
+  getter sub_type : String
 
   def initialize(value : String)
     super value
 
-    @type = "*/*" if @type == "*"
+    @accept_value = "*/*" if @accept_value == "*"
 
-    parts = @type.split '/'
+    parts = @accept_value.split '/'
 
     if parts.size != 2 || !parts[0].presence || !parts[1].presence
-      raise ANG::Exceptions::InvalidMediaType.new @type
+      raise ANG::Exceptions::InvalidMediaType.new @accept_value
     end
 
-    @base_part = parts[0]
+    @type = parts[0]
-    @sub_part = parts[1]
+    @sub_type = parts[1]
+  end
+
+  # Returns the media range this `Accept` header represents.
+  #
+  # I.e. `#header` minus the `#quality` and `#parameters`.
+  def media_range : String
+    @accept_value
   end
 end

src/accept_charset.cr

@@ -1,4 +1,21 @@
 require "./base_accept"
 
+# Represents an [Accept-Charset](https://tools.ietf.org/html/rfc7231#section-5.3.3) header character set.
+#
+# ```
+# accept = ANG::AcceptCharset.new "iso-8859-1; q = 0.5; key=value"
+#
+# accept.header            # => "iso-8859-1; q = 0.5; key=value"
+# accept.normalized_header # => "iso-8859-1; key=value"
+# accept.parameters        # => {"key" => "value"}
+# accept.quality           # => 0.5
+# accept.charset           # => "iso-8859-1"
+# ```
 struct Athena::Negotiation::AcceptCharset < Athena::Negotiation::BaseAccept
+  # Returns the character set this `AcceptCharset` header represents.
+  #
+  # I.e. `#header` minus the `#quality` and `#parameters`.
+  def charset : String
+    @accept_value
+  end
 end

src/accept_encoding.cr

@@ -1,4 +1,21 @@
 require "./base_accept"
 
+# Represents an [Accept-Encoding](https://tools.ietf.org/html/rfc7231#section-5.3.4) header character set.
+#
+# ```
+# accept = ANG::AcceptEncoding.new "gzip; q = 0.5; key=value"
+#
+# accept.header            # => "gzip-1; q = 0.5; key=value"
+# accept.normalized_header # => "gzip-1; key=value"
+# accept.parameters        # => {"key" => "value"}
+# accept.quality           # => 0.5
+# accept.coding            # => "gzip"
+# ```
 struct Athena::Negotiation::AcceptEncoding < Athena::Negotiation::BaseAccept
+  # Returns the content coding this `AcceptEncoding` header represents.
+  #
+  # I.e. `#header` minus the `#quality` and `#parameters`.
+  def coding : String
+    @accept_value
+  end
 end

src/accept_language.cr

@@ -1,27 +1,55 @@
 require "./base_accept"
 
+# Represents an [Accept-Language](https://tools.ietf.org/html/rfc7231#section-5.3.5) header character set.
+#
+# ```
+# accept = ANG::AcceptLanguage.new "zh-Hans-CN; q = 0.3; key=value"
+#
+# accept.header            # => "zh-Hans-CN; q = 0.3; key=value"
+# accept.normalized_header # => "zh-Hans-CN; key=value"
+# accept.parameters        # => {"key" => "value"}
+# accept.quality           # => 0.3
+# accept.language          # => "zh"
+# accept.region            # => "cn"
+# accept.script            # => "hans"
+# ```
 struct Athena::Negotiation::AcceptLanguage < Athena::Negotiation::BaseAccept
+  # Returns the language for this `AcceptLanguage` header.
+  # E.x. if the `#language_range` is `zh-Hans-CN`, the language would be `zh`.
   getter language : String
-  getter script : String? = nil
+
+  # Returns the region, if any, for this `AcceptLanguage` header.
+  # E.x. if the `#language_range` is `zh-Hans-CN`, the language would be `cn`
   getter region : String? = nil
 
+  # Returns the script, if any, for this `AcceptLanguage` header.
+  # E.x. if the `#language_range` is `zh-Hans-CN`, the language would be `hans`
+  getter script : String? = nil
+
   def initialize(value : String)
     super value
 
-    parts = @type.split '-'
+    parts = @accept_value.split '-'
 
     case parts.size
+    when 1
+      @language = parts[0]
     when 2
       @language = parts[0]
       @region = parts[1]
-    when 1
-      @language = parts[0]
     when 3
       @language = parts[0]
       @script = parts[1]
       @region = parts[2]
     else
-      raise ANG::Exceptions::InvalidLanguage.new @type
+      raise ANG::Exceptions::InvalidLanguage.new @accept_value
     end
   end
+
+  # Returns the language range this `AcceptLanguage` header represents.
+  #
+  # I.e. `#header` minus the `#quality` and `#parameters`.
+  def language_range : String
+    @accept_value
+  end
 end

src/accept_match.cr

@@ -1,3 +1,4 @@
+# :nodoc:
 struct Athena::Negotiation::AcceptMatch
   include Comparable(self)
 

src/athena-negotiation.cr

@@ -13,16 +13,91 @@ require "./exceptions/*"
 # Convenience alias to make referencing `Athena::Negotiation` types easier.
 alias ANG = Athena::Negotiation
 
+# The `Athena::Negotiation` component allows an application to support [content negotiation](https://tools.ietf.org/html/rfc7231#section-5.3).
+# The component has no dependencies and is framework agnostic; supporting various negotiators.
+#
+# ## Usage
+#
+# The main type of `Athena::Negotiation` is `ANG::AbstractNegotiator` which is used to implement negotiators for each `Accept*` header.
+# `Athena::Negotiation` exposes class level getters for each negotiator; that return a lazily initialized singleton instance.
+# Each negotiator exposes two methods: `ANG::AbstractNegotiator#best` and `ANG::AbstractNegotiator#ordered_elements`.
+#
+# ### Media Type
+#
+# ```
+# negotiator = ANG.negotiator
+#
+# accept_header = "text/html, application/xhtml+xml, application/xml;q=0.9"
+# priorities = ["text/html; charset=UTF-8", "application/json", "application/xml;q=0.5"]
+#
+# accept = negotiator.best(accept_header, priorities).not_nil!
+#
+# accept.media_range # => "text/html"
+# accept.parameters  # => {"charset" => "UTF-8"}
+# ```
+#
+# The `ANG::Negotiator` type returns an `ANG::Accept`, or `nil` if negotiating the best media type has failed.
+#
+# ### Character Set
+#
+# ```
+# negotiator = ANG.charset_negotiator
+#
+# accept_header = "ISO-8859-1, UTF-8; q=0.9"
+# priorities = ["iso-8859-1;q=0.3", "utf-8;q=0.9", "utf-16;q=1.0"]
+#
+# accept = negotiator.best(accept_header, priorities).not_nil!
+#
+# accept.charset # => "utf-8"
+# accept.quality # => 0.9
+# ```
+#
+# The `ANG::CharsetNegotiator` type returns an `ANG::AcceptCharset`, or `nil` if negotiating the best character set has failed.
+#
+# ### Encoding
+#
+# ```
+# negotiator = ANG.encoding_negotiator
+#
+# accept_header = "gzip;q=1.0, identity; q=0.5, *;q=0"
+# priorities = ["gzip", "foo"]
+#
+# accept = negotiator.best(accept_header, priorities).not_nil!
+#
+# accept.coding # => "gzip"
+# ```
+#
+# The `ANG::EncodingNegotiator` type returns an `ANG::AcceptEncoding`, or `nil` if negotiating the best character set has failed.
+#
+# ### Language
+#
+# ```
+# negotiator = ANG.language_negotiator
+#
+# accept_header = "en; q=0.1, fr; q=0.4, zh-Hans-CN; q=0.9, de; q=0.2"
+# priorities = ["de", "zh-Hans-CN", "en"]
+#
+# accept = negotiator.best(accept_header, priorities).not_nil!
+#
+# accept.language # => "zh"
+# accept.region   # => "cn"
+# accept.script   # => "hans"
+# ```
+#
+# The `ANG::LanguageNegotiator` type returns an `ANG::AcceptLanguage`, or `nil` if negotiating the best character set has failed.
 module Athena::Negotiation
-  # Returns an `ANG::Negotiator` singleton instance.
+  # Returns a lazily initialized `ANG::Negotiator` singleton instance.
   class_getter(negotiator) { ANG::Negotiator.new }
 
-  # Returns an `ANG::CharsetNegotiator` singleton instance.
+  # Returns a lazily initialized `ANG::CharsetNegotiator` singleton instance.
   class_getter(charset_negotiator) { ANG::CharsetNegotiator.new }
 
-  # Returns an `ANG::EncodingNegotiator` singleton instance.
+  # Returns a lazily initialized `ANG::EncodingNegotiator` singleton instance.
   class_getter(encoding_negotiator) { ANG::EncodingNegotiator.new }
 
-  # Returns an `ANG::LanguageNegotiator` singleton instance.
+  # Returns a lazily initialized `ANG::LanguageNegotiator` singleton instance.
   class_getter(language_negotiator) { ANG::LanguageNegotiator.new }
+
+  # Contains all custom exceptions defined within `Athena::Negotiation`.
+  module Exceptions; end
 end

src/base_accept.cr

@@ -1,14 +1,28 @@
+# Base type for properties/logic all [Accept*](https://tools.ietf.org/html/rfc7231#section-5.3) headers share.
 abstract struct Athena::Negotiation::BaseAccept
-  getter quality : Float32 = 1.0
+  # Returns the full unaltered header `self` represents.
-  getter normalized_value : String
+  # E.x. `text/html` or `unicode-1-1;q=0.8` or `zh-Hans-CN`.
-  getter value : String
+  getter header : String
-  getter parameters : Hash(String, String) = Hash(String, String).new
-  getter type : String
 
-  def initialize(@value : String)
+  # Returns a normalized version of the `#header`, excluding the `#quality` parameter.
-    # type, parameters = self.parse_accept_value value
+  #
-    parts = @value.split ';'
+  # This includes removing extraneous whitespace, and alphabetizing the `#parameters`.
-    @type = parts.shift.strip.downcase
+  getter normalized_header : String
+
+  # Returns any extension parameters included in the header `self` represents.
+  # E.x. `charset=UTF-8` or `version=2`.
+  getter parameters : Hash(String, String) = Hash(String, String).new
+
+  # Returns the [quality value](https://tools.ietf.org/html/rfc7231#section-5.3.1) of the header `self` represents.
+  getter quality : Float32 = 1.0
+
+  # Represents the base header value, e.g. `#header` minus the `#quality` and `#parameters`.
+  # This is exposed as a getter on each subtype to have a more descriptive API.
+  protected getter accept_value : String
+
+  def initialize(@header : String)
+    parts = @header.split ';'
+    @accept_value = parts.shift.strip.downcase
 
     parts.each do |part|
       part = part.split '='
@@ -20,16 +34,16 @@ abstract struct Athena::Negotiation::BaseAccept
     end
 
     if quality = @parameters.delete "q"
-      @quality = quality.to_f32
+      # RFC Only allows max of 3 decimal points.
+      @quality = quality.to_f32.round 3
     end
 
-    @normalized_value = String.build do |io|
+    @normalized_header = String.build do |io|
-      io << @type
+      io << @accept_value
 
       unless @parameters.empty?
         io << "; "
-        # TODO: Do we care the parameters aren't sorted?
+        @parameters.keys.sort!.join(io, "; ") { |k, join_io| join_io << "#{k}=#{@parameters[k]}" }
-        parameters.join(io, "; ") { |(k, v), join_io| join_io << "#{k}=#{v}" }
       end
     end
   end

src/charset_negotiator.cr

@@ -1,5 +1,6 @@
 require "./abstract_negotiator"
 
+# A `ANG::AbstractNegotiator` implementation to negotiate `ANG::AcceptCharset` headers.
 class Athena::Negotiation::CharsetNegotiator < Athena::Negotiation::AbstractNegotiator
   private def create_header(header : String) : ANG::BaseAccept
     ANG::AcceptCharset.new header

src/encoding_negotiator.cr

@@ -1,5 +1,6 @@
 require "./abstract_negotiator"
 
+# A `ANG::AbstractNegotiator` implementation to negotiate `ANG::AcceptEncoding` headers.
 class Athena::Negotiation::EncodingNegotiator < Athena::Negotiation::AbstractNegotiator
   private def create_header(header : String) : ANG::BaseAccept
     ANG::AcceptEncoding.new header

src/exceptions/invalid_language.cr

@@ -1,7 +1,11 @@
 require "./negotiation_exception"
 
-class Athena::Negotiation::Exceptions::InvalidLanguage < Athena::Negotiation::Exceptions::Exception
+# Represents an invalid `ANG::AcceptLanguage` header.
-  def initialize(type : String, cause : Exception? = nil)
+class Athena::Negotiation::Exceptions::InvalidLanguage < Athena::Negotiation::Exceptions::Negotiation
-    super type, "Invalid language: '#{type}'.", cause
+  # Returns the invalid language code.
+  getter language : String
+
+  def initialize(@language : String, cause : Exception? = nil)
+    super "Invalid language: '#{@language}'.", cause
   end
 end

src/exceptions/invalid_media_type.cr

@@ -1,7 +1,11 @@
 require "./negotiation_exception"
 
-class Athena::Negotiation::Exceptions::InvalidMediaType < Athena::Negotiation::Exceptions::Exception
+# Represents an invalid `ANG::Accept` header.
-  def initialize(type : String, cause : Exception? = nil)
+class Athena::Negotiation::Exceptions::InvalidMediaType < Athena::Negotiation::Exceptions::Negotiation
-    super type, "Invalid media type: '#{type}'.", cause
+  # Returns the invalid media range.
+  getter media_range : String
+
+  def initialize(@media_range : String, cause : Exception? = nil)
+    super "Invalid media type: '#{@media_range}'.", cause
   end
 end

src/exceptions/negotiation_exception.cr

@@ -1,7 +1,4 @@
-abstract class Athena::Negotiation::Exceptions::Exception < ::Exception
+# Base type of all `Athena::Negotiation` errors.
-  getter type : String
+# Can be used to rescue any exception originating from `Athena::Negotiation`.
-
+abstract class Athena::Negotiation::Exceptions::Negotiation < ::Exception
-  def initialize(@type : String, message : String? = nil, cause : Exception? = nil)
-    super message, cause
-  end
 end

src/language_negotiator.cr

@@ -1,5 +1,6 @@
 require "./abstract_negotiator"
 
+# A `ANG::AbstractNegotiator` implementation to negotiate `ANG::AcceptLanguage` headers.
 class Athena::Negotiation::LanguageNegotiator < Athena::Negotiation::AbstractNegotiator
   protected def match(accept : ANG::AcceptLanguage, priority : ANG::AcceptLanguage, index : Int32) : ANG::AcceptMatch?
     accept_base = accept.language

src/negotiator.cr

@@ -1,15 +1,16 @@
 require "./abstract_negotiator"
 
+# A `ANG::AbstractNegotiator` implementation to negotiate `ANG::Accept` headers.
 class Athena::Negotiation::Negotiator < Athena::Negotiation::AbstractNegotiator
   # TODO: Make this method less complex.
   #
   # ameba:disable Metrics/CyclomaticComplexity
   protected def match(accept : ANG::Accept, priority : ANG::Accept, index : Int32) : ANG::AcceptMatch?
-    accept_base = accept.base_part
+    accept_type = accept.type
-    priority_base = priority.base_part
+    priority_type = priority.type
 
-    accept_sub = accept.sub_part
+    accept_sub_type = accept.sub_type
-    priority_sub = priority.sub_part
+    priority_sub_type = priority.sub_type
 
     intercection = accept.parameters.each_with_object({} of String => String) do |(k, v), params|
       priority.parameters.tap do |pp|
@@ -17,50 +18,50 @@ class Athena::Negotiation::Negotiator < Athena::Negotiation::AbstractNegotiator
       end
     end
 
-    base_equal = accept_base.downcase == priority_base.downcase
+    type_equals = accept_type.downcase == priority_type.downcase
-    sub_equal = accept_sub.downcase == priority_sub.downcase
+    sub_type_equals = accept_sub_type.downcase == priority_sub_type.downcase
 
     if (
-         (accept_base == "*" || base_equal) &&
+         (accept_type == "*" || type_equals) &&
-         (accept_sub == "*" || sub_equal) &&
+         (accept_sub_type == "*" || sub_type_equals) &&
          intercection.size == accept.parameters.size
        )
-      score = 100 * (base_equal ? 1 : 0) + 10 * (sub_equal ? 1 : 0) + intercection.size
+      score = 100 * (type_equals ? 1 : 0) + 10 * (sub_type_equals ? 1 : 0) + intercection.size
 
       return ANG::AcceptMatch.new accept.quality * priority.quality, score, index
     end
 
-    return nil if !accept_sub.includes?('+') || !priority_sub.includes?('+')
+    return nil if !accept_sub_type.includes?('+') || !priority_sub_type.includes?('+')
 
-    accept_sub, accept_plus = self.split_sub_part accept_sub
+    accept_sub_type, accept_plus = self.split_sub_type accept_sub_type
-    priority_sub, priority_plus = self.split_sub_part priority_sub
+    priority_sub_type, priority_plus = self.split_sub_type priority_sub_type
 
     if (
-         !(accept_base == "*" || base_equal) ||
+         !(accept_type == "*" || type_equals) ||
-         !(accept_sub == "*" || priority_sub == "*" || accept_plus == "*" || priority_plus == "*")
+         !(accept_sub_type == "*" || priority_sub_type == "*" || accept_plus == "*" || priority_plus == "*")
        )
       return nil
     end
 
-    sub_equal = accept_sub.downcase == priority_sub.downcase
+    sub_type_equals = accept_sub_type.downcase == priority_sub_type.downcase
-    plus_equal = accept_plus.downcase == priority_plus.downcase
+    plus_equals = accept_plus.downcase == priority_plus.downcase
 
     if (
-         (accept_sub == "*" || priority_sub == "*" || sub_equal) &&
+         (accept_sub_type == "*" || priority_sub_type == "*" || sub_type_equals) &&
-         (accept_plus == "*" || priority_plus == '*' || plus_equal) &&
+         (accept_plus == "*" || priority_plus == '*' || plus_equals) &&
          intercection.size == accept.parameters.size
        )
-      score = 100 * (base_equal ? 1 : 0) + 10 * (sub_equal ? 1 : 0) + (plus_equal ? 1 : 0) + intercection.size
+      score = 100 * (type_equals ? 1 : 0) + 10 * (sub_type_equals ? 1 : 0) + (plus_equals ? 1 : 0) + intercection.size
       return ANG::AcceptMatch.new accept.quality * priority.quality, score, index
     end
 
     nil
   end
 
-  private def split_sub_part(sub_part : String) : Array(String)
+  private def split_sub_type(sub_type : String) : Array(String)
-    return [sub_part, ""] unless sub_part.includes? '+'
+    return [sub_type, ""] unless sub_type.includes? '+'
 
-    sub_part.split '+', limit: 2
+    sub_type.split '+', limit: 2
   end
 
   private def create_header(header : String) : ANG::BaseAccept